Worm element lapping machine



Jly 30, 1940 l .l. c. DRADER ET A1. 42,209,562

woxw ELEMENT LAPPING MACHINE l 'I .Filed April 15, 193s 4 sheets-sheet 1 .ya @L INVENTOR5- A July 30, 1940. J. c. DRADER Er l 2,209,562 Wonu ELEMENT LAPPING MAQHINE, I

Filed April-15. 195s sheets-sheet s' Y INVENToRaf J'dey 5- Ai y J'Mf 47@- A TTORNEYS.

Patented July 1940 v UNITED STATES PATENT OFFICE Joseph o. under, neu-oit, and. James Maren, f

Ferndale, Mich., assignors to Michigan Tool'. Company, a corporation of Delaware Application April 1s, 1936ser1a1 No. 74,45

4 a claims. (ci. 51-2m The present invention relates to gear finishing machines and, in particular, provides an improved machine for lapping or otherwise ilnishing worm gears of the type in which'the pitch 5 circle of the teeth is eccentrically positioned with reference to the axis of the gear.

Objects of the present invention are to provide an improved gear nishing machine adapted particularly to the lapping or otherwise n' ishing of worm gears; to provide such a machine in which a worm gear and a cooperating lapping tool may bel run together to effectively lap the worm gear; to provide such a machine, in accordance with one embodiment of which,` the worm gear is driven and all or certain of the 'finishing tools are driven thereby and are suitably braked to impose a load thereon; to provide such a machine, in accordance with a second embodiinent of which, one tool is provided to drive zo the worm gear,.and one or more additional tools may be related to the worm gear in driven relation thereto and suitably braked to impose a load thereon. l p

Further objects of the present invention are to provide an improvedrmachine'for lapping or for otherwise finishing worm gears embodying one or more-movable supports for positioning a tool in adjustable relation to the worm gear; to provide such a machine in which one orl more tools are rotatably mounted upon slides which are Y movable toward and away from the axis of the worm gear; to provide improved means for `simultaneously -controlling the'inward and outward movement of a'. plurality of tool carrying a5 slides; to provide improved releasable means for retaining the tools in working position with reference to the worm gear.

Further objects of the present invention are to provide such a machine embodying improved and 40 readily adjustable means for accurately positioning and rotatably supporting a worm gear in working relation to one or more tools.

Further objects of the present invention are to provide a machine .for lapping or otherwise finishing worm gears of the globoidal type and w'embodying improved'adjustable means for aecurately positioning the axis of rotation of one or more tools with reference to the axis of, the

Further objects of the present invention are` such a machine embodying improved means to support the worm or other gear for rotation about the axis of the pitch circle.

With the above and other objectsin view,

which appear in the following description and in 5 I the appended claims, preferred embodiments of the present invention are shown, in the accompanying drawings, throughout which corresponding reference characters are used to designa corresponding parts, and in which:

Figure 1 is a perspective view in front elevation of one embodiment of the present invention;

Figure 1A is a view in horizontal section taken along the line IA-IA of Fig. 4;

Fig. 2 is a perspective view in a rearelevation l5 of Fig. 1: Y

Fig. 3 is a view ing-vertical central section taken along the lines 3 3 of Fig. 1; Y

Fig. 4 is a detail view, partly in vertical ce trai section, taken along the line 4--4 of Fig. 1;

Fig. 5 is a fragmentary view in elevation, taken along the line 5-5 of Fig. 1

v Fig. 6 is a fragmentary view in detail with certain parts broken away. taken along the line 6 6 oi' Fig. v5; and

Fig. 'I is a partial view n front elevation of a modified embodiment of the present invention.

,Considering rst the general views, Figures 1Y and 2, the wormV I0 to be lapped or otherwise nished is supported for rotation about a ver# tical axis, and the cooperating tools, illustrated as lapping tools I2, and two which are shownin the drawings, are disposed on respectively op posite sides` of the worm'. I0 and Yare supported with their axesf horizontal. The worm Iliand 'tools I2, as well as the mechanism for adjusting the positions thereof, `and for running them together, are supported as a whole in generally elevated relation upon a machine base I6, the necessary operating parts thereof being accessible from the 4front of the machine, and certain of the control and power elements, such as switches. etc., being supported in cabinetsY such as i8 at the rear of the machine. It will be appreciated thatthe teeth of tools I! are such that they suitably mate with the-teeth of the worm element I0, the exact form thereof being dependent upxid the speciiic m'shing operation contem-l p a Y Referring particularly to Figure -4, worm Il, which is of the globoidal or Hindley type, is mounted, with its axis vertical, between an upper or 'driving spindle designated generally as 20, and a lower spindle designated generally as 22.

The upper or driving spindle 2l is rotatably 55 or integrally formed with the upwardly extending frame portion 26, and disposed in forwardly extending relation thereto. The driving spindlev v28 comprises generally an inner or driving core 28, to the upper end of whicha suitable external driving element represented as the pulley 38 is keyed by key 32, and secured in place axially of core 28 by nut 34. The lower portion 36 of core 28 is tapered, and cooperates with a correspondingly and oppositely tapered bearing member 38 to form therewith a bearing adapted to. take both radial and axial thrust. A similarly tapered bearing sleeve 48 is keyed by key 4 2 to core 28 and cooperates with a second tapered bearing member 44.to form a radial and thrust bearing. Sleeve 48 is secured in place axially of core 28 by a collar 46, keyed thereto by key 48, and set screw 48, which jams key 49 against core 28. The two bearing members 38 and 44 are fitted into an adjusting sleeve 58, provided with annu- `lar shoulders 52 and 54, which cooperate with correspondingly formed annular shoulders in the bearing members to determine the positions of the latter within thev sleeve 58.` Members 38 and 44 are provided with recesses 38 and 45, which receive locking pins 31 and 41. Sleeve 58 is slidable within the previously mentioned boss 24, but is secured against rotation relative thereto by a set screw 56, the inner end of which enmembers 48 and 38 respectively, and form oil pockets therein, in communication with annular `grooves 68 and 18, also formed in the bearing members. 'Ihe lower end of bearing member 48 is slotted at 12 and a -corresponding slot 14 `is formed at the upper end of bearing member 38, to afford communication between the pockets 64 and 66. Oil may be introduced through-a lateral passage 1-6, which may communicate with a suitable source of lubricant, such as one of the oil cups 'I8 shown in Figure 1. Oil thus introduced nowsaround the annular groove 68 formed in bearing member 48 and collects inpockets 64, from which it drains through the slots 12 and. 14 into and.collects in pocket 66. The lower end of core 28 is provided with a base plate82, se-

cured thereto by countersunk studs 84, and asuitable packing gland such as 86 is interposed between base plate 82 and the lower and downwardy extending end 88 of sleeve 58, to prevent the escape of lubricant between these members. A conventional tapered center 88 is received in a correspondinglyltapered passage 88 formed in core 28, which is also provided'with a passage' 82 through which a suitable tool may bevinserted to drive center 88 out of passage 88 when desired. The lower end 84 of core 28 extends partf way into the central opening formed in base plate 82, and on its bottom face is provided with a radially extending key 86, which enters a keyway 88 formed in thechuck |88, to form a driving connection. therebetween, as described in nere detail below.

' "l'hlower @india-designated generally as 22, comprises a conventional deadl center |82, the center point of-which cooperates with the worm assembly, as described in more detail below, and the other and tapered shank |84 of which is received in a correspondingly tapered bore formed in an adjusting sleeve |86. A deecting apron |85 is preferably carried by center |82 to protect the adjustingv structure thereof. Adjusting sleeve |86 is slidably mounted in 'a bushing |88 fitted into a lower boss II8, which extends forwardly from the machine frame 26, in axial alignment with the upper boss 24. Sleeve |86 is provided with rack teeth 2 on its-surface with which a pinion II4 meshes. Pinion 4 is suitably secured to an adjusting shaft II 6 to provide an upward and downward adjustment of the lower spindle 22 withreference to the upper spindle 28. As also shown in Figure 1, shaft I|6 is suitably journaled in boss ||8 and at its outer end is provided with hand wheels ||8 which may be manually operated to turn pinion |I4, and cause the driving spindle 22 to correspondingly move upwardly and downwardly within boss ||8. Any suitable and conventional means (not shown) may be utilized to lock shaft I|6 in each selected position of adjustment.

. As previously stated, an importantfeature'of the present invention is an improved arrangement for supporting a worm gear, the pitch cirj. cle of which is eccentric to the intended axis of rotation of .the gear, so that the pitch circle is concentric with the driving ispindle. In the illustrated arrangement, and ,in accordance with conventional practice, worm gear I8 is provided is splined to provide a driving .relation therebetween. The opposite ends .of shaft |22 are keyed by keys |24 and. |26 within the previously mentioned chuck |88 and a corresponding lower chuck |28 respectively, The upper en d of shaft |22 is provided with ai: tapered recess |38, which receives the pointed end of center V88, Aand is eccentric vto the axis of shaft |22 toa' degree corresponding to the eccentricity of the pitch circle of worm I8. The splined relation between worm gear I8 and shaft |22 is such that these members when fitted together occupy a relative rotative position, which renders center 88 concentric with the pitch circle of worm gear I8. Similarly, the re'cess |32 formed in the lower face of the lower chuck |28 is in axial alignment with center 88, and is eccentric with reference to the axis of shaft |22, to the same extent, and is tapered recesses |34 and |36 respectively, which' receive the correspondingly4 tapered' ends oi' worm gear I8. The last mentioned tapered ends of worm I8 mayl beexpected to beconcentric with an axial bore |28 whichfextends entirely "therethrough, and into which a short shaft |22 with the bore of worm I 8, i. e. eccentric to the 4 pitch circle thereof, so that recesses |34 and |36 are` correspondingly eccentric to the axes of centers 88 and |82.

Considering now the supporting structure for the lapping or other finishing "tools I2, and referring particularly to. Figures 1 through 6, each tool I2 is keyed by a key |42 onv the'outer end of a shaft |44, and is removably iixed inplace axially thereof between a lock nut |46 anda collar |48, which bears against a face plate v |58. Plate |58 is secured to shaft |44 by studs |52 and is provided with a protective flange |5I, -which cooperates with a tubular member |88, urged out-`v wardly by spring |58, in preventing the cutting l t I accesso spindle`20, and including the bearing members |56, |58 and |60. Each boss |54 in either suitably secured to or integrally formed with an associated silde |62, the rear face of which as viewed in Figure 1 is provided with a dovetail |64 which rides lin a correspondingly formed way |66 formed in the frame portion 26. Preferably and as illustrated, a tapered gib |68 is provided to take up any wear between the dovea tail |64 and the way |66. Gib |68 is interposed directly between the upper edge of the dovetail |64 and frame portion 26, as best seen in Fig- `ures 1 and 4, and is secured in place by an adjusting screw provided with lock nuts |12 and |14, by which the gib may be withdrawn or advanced into the frame, member to thereby restrict or enlarge the space provided for dovetail |64.

The rear end of each boss |54, as best seen in Figures 2 and 3, acts as a support for a conven- Y 25. tional uid brake mechanism |16, secured thereto by studs |18 which pass through cooperating anges |80 and |82 formed on the brake housing and boss |54 respectively. Each brake shaft |11 is splined to the associated shaft |44. The constuction of the brake mechanism forms no part of the present invention and has not been illustrated in detail, it being understood that each braking mechanism is independently adjustable to impose am desired braking torque upon the shaft- |44 associated therewith and consequentlythe particular tool |2 associated therewith. Mete's such as |84 are conventionally provided to indicate the braking load thus. im-` posed.

In further accordance with the present invention, -the lapping V tool carrying slides |62 are simultaneously adjustable toward and away from Aeach other to correspondingly advance the tools into 'working relationship and outl of working reteeth |96 and |98 respectively, and are guided' in slots 200 and 202 respectively formed in a bracket- 204 lwhich is suitably secured to :the

main machine'frame portion 26. An adjusting shaft 206 is suitably iournaled inthe bracket 204 and in the'main machine frame 26, and carries at its inner 'end a pin 206, which meshes vwith the previously mentioned racks |96 andl98. At its outerend, the shaft 206 is provided with the manual controlA member 2|0, formed crank for convenience of operation.

As is evident. from inspection of Figure 6, ro-

tation of bell crank 2|0 in a clockwise direction,

causes push rod |90 to move to the right' and' push rod |94 to move to the left, thus separating theslides |62 and moving the lapping tools |2 out of mating relation with the worm gear I0.'

Rotation of bell crank 2|0 in a counter-clockwise direction eiects 'a reverse operation, bringing slidesl62 and consequently-lapping tools |2 to-` \gether. Ansautogtic limit to the degree` of inward movement of tle lapping-tools |`2 with reference to the worm gears I0' is provided by la asabellv 3 locking plate 2|2 and a cooperating dog 2|4.

Locking plate 2|2 is secured in iixed relation to bracket 204 by studs 2|6 and dog 2|4 is pivotally supported on bellcrank 2| 0 by trunnion 2|8. A-

tension spring 220 connected between the end ofl 6 dog 2|4 and a pin 222 secured to and movablewith bell ,crank 2|0 urges dog 2|4 to the position shown in Figure 6. The nose 224 of dog 2|4 is adapted to be received in a corresponding notch 226 cut in the periphery of plate 2|2. The l0 right hand face of notch 226, as viewed in Figure 6, and the corresponding face of dog 224 are so angled as to meet in positive locking relation, to impose a positive limit'to a counter-clockwise rotation of bell crank 2|0,' and to impose `a cor- 15 responding limit to inward movement of the lap- .ping tools l2 with reference to gears I0. 'Ihe opposite or left hand faces of notch 226 and nose 224, however, as viewed in Figure 6, are less abruptly angled, and permit clockwise rotation of 20 bell 'crank 2|0, such rotation camming dog 2|4 out-of notch 226 against theI force of spring 220, and causing it to thereafter ride along the periphery of locking plate 2|2. It will be noted, accordingly, that the means including spring 220 25 and'dog 2|4 acts to yieldingly oppose a separating movement of the tools. lA limit to such clockwise rotation isprovided by a pin 228 projecting 'from bell crank 2|0 and adapted to engage a shoulder 260 formed in theiocking plate 30 22. Upon lowering the ldpver driving spindle 22 40 by means of the hand wheel I8, a worm gear and cooperating parts including the sha-ft |22 and chucks |00 and 4|28. with which the gear may previously have been assembled, maybe moved Y into engagement with the driving spindle 28, key 45 96 in the latter entering the keyway 98 formed in chuck |00 to effect a driving connection therebetween. Thereafter, the lower spindle 22 may be moved upwardly, bringing the dead center |02 into cooperative engagement with the lower 66 collar |28. a In the lapping o r otherwise nishing of globoidal worms, it is cssential'that the axis of the r lapping or other nishing tools accurately coincide with the axial center of the worm gear. and 55 this adjustment, in accordance with the present construction, may readily be effected by the ad- Justing nuts 60 and 62 associatedwlth the previously described sleeve 50, and which may be advanced or backed ofi to raise or lower sleeve 50 so and consequently the driving spindles 20 with reference to the tools i2.

Upon completing the above 4initial adjustments and the chucking of gear l0 between spindles 20 and 22, the bell crank 2|0 may be rotated in a 65 counter-clockwise direction, which action moves slides |62 and consequently lapping tools I2 toward each other, until the no'se 224 of dog 2|4 drops into the, notch 226 formed in the locking plate 2|2. This latter action interrupts the coun- '70 ter-clockwise rotation of bell crank 2 I0 and determines the operating positionof the lapping tools |2 with reference to thel worm gear I0. This iinal operating position is' preferably accurately adjustable and for this purposein the illustrated i 75 y construction, the push rods I l0 and I are adjustable longitudinally of the associated slides I62 by the lock nuts 232 and 234, which may be backed oil' or advanced, to correspondingly move the push rods with respect to the bosses |92 and |95. The adjustment thus effected is preferably such that in the operating position, the crowns of the tool teeth are spaced slightly from the roots of the worm gear teeth, a corresponding spacing existingof course between the crowns of the Vworm gear teeth and the roots of the tool teeth.

Upon starting driving spindle 22 in rotation,

which may be effected in the present instance by motor` 236, which drives the previously mentioned pulley 30 through belt 238, worm gear Ill runs in mesh and' correspondingly rotates the two lapping tools I2, each of which as previously described are subjected to a braking load of selectively and independently adjustable magnitude through the fluid brakes |16. For lapping operations, it is preferred to use tools, the teeth of which are of insuiiicient width to have fullmating contact with the teeth of the worm gear I0, so that during rotation of worm gear I0 in one direction, only one tooth face is lapped. To effect the lapping ofthe opposite tooth faces, the direction of rotation-of the worm I0 may be reversed or alternatively, the worm may be removed from the machine, and inverted, as will be understood.

In the alternative construction, shown in Figure '7, the general arrangement is as described with reference to the preceding gures. 'I'he worm element is supported on centers carried in bosses 24 and lill', which in turn are carried upon the portion 25' ofthe base IB. 'Ihe lapping tools I 2' are supported on slides i621' which are controlled by a bell crank 2I0. As modied, however, the

driving motor 236' is connected through belt 238' to drive one of the tools I2' through a pulley 240 which may be mounted on the shaft of the latter. With this arrangement, the braking mechanism associated with the driven tool I2" is eliminated, and the direct driving connection between the driving motor and the worm gear I0 is also eliminated. braked as described with reference to the preceding i'lgures. With this arrangement, the externally driven tool I 2' laps one worm tooth face,

50 and the other lapping tool i2 laps the other tooth The other tool I2' is preferably face, thus permitting the lapping of both tooth faces in a single lapping operation.

Although specific embodiments of the present invention have been shown and described, it will be understood that various modifications in the form, number and arrangement of parts may be made therein within the spirit and present invention.

' What is claimed is:

1. In a machine for finishing worm elem'ents of the type in which the pitch circle is eccentric to the axis of a passage through the worm, means for supporting said worm for rotation about the axis of the pitch circle comprising a shaft passed through said worm passage in axial coincidence therewith and splined thereto; a collar fitted over said shaft and engaging said worm; means come prising a key for non-rotatively connecting said collar to said shaft; and means for rotating said collar about an axis coincident with the center of of said pitch circle.

2. In a gear finishing machine means for supporting a gear for rotation; a pair of finishing tools; means including a slide individual to each finishing tool for supporting thesame; and means for simultaneously actuating said slides to move said tools toward and away from said gear comprising a pivotally mounted arm; a stationarily 'supported cam plate; means including a dog carried by said arm and cooperating with said cam plate to yieldingly oppose rotation of said arm in a direction to withdraw said tools from said gear and to impose a positive limit to movement of said arm in a direction to cause said tools to approach said gear.

3. In a machine for finishing worm elements of the type in which the pitch circle is eccentric to the axis of a passage through the worm element, means for supporting said worm element forrotation about the axis of the pitch circle comprising a shaft passed through said worm passage in axial coincidence with said passage and drivingly connected to said worm element, a collar removably tltted over said shaft and engaging said worm.,y a driving connection' between said collar and said shaft, and means for rotating said collar about an axis coincident with the center of said pitch circle.

' JOSEPH C. DRADER.

lJAMES MARTIN.

scope of the 

